1. Field of the Invention
This invention relates generally to an electromagnetic contactor, and more particularly to a construction for mounting an attachment or accessory, containing additional function-performing electric components such as a surge-suppressing element and an operation-indicating lamp, to the body of the electromagnetic contactor. Preferably, such attachment can be removably attached to the electromagnetic contactor even after the electromagnetic contactor has been connected to a switchboard.
2. Prior Art
In order that an attachment can be releasably attached to an electromagnetic contactor even after the electromagnetic contactor has been connected to a switchboard, there has been known an electromagnetic contactor which has a first engaging portion formed on the surface of a side wall thereof, and an attachment casing which also has a second engaging portion which is resiliently engageable with the first engaging portion, thereby attaching the attachment to the electromagnetic contactor by one touch.
With such a conventional arrangement, the attachment can be easily attached to the electromagnetic contactor; However, whether the attachment is attached to the electromagnetic contactor in intimate contact therewith or not depends on the condition of engagement between the first and second engaging portions. Generally since the electromagnetic contactor is subjected to vibration each time it is operated, a considerable burden is imposed on lead wires extending from the attachment to the electromagnetic contactor if the contact between the attachment and the electromagnetic contactor is not sufficiently intimate. Moreover, in the worst case, the attachment is disengaged from the electromagnetic contactor. Further, connecting elements of the attachment are not electrically insulated. In order to provide a good electrical insulation between the connecting elements and the electromagnetic contactor, it has been required to provide an adequate distance between the electromagnetic contactor and the attachment. This results in a problem that the resultant assembly composed of the electromagnetic contactor and the attachment fails to be of a compact-size. Further, there is a risk that some object may be brought into contact with the connecting elements.